1. Field of the Invention
The present invention relates generally to communications between transceiver devices.
2. Background Art
The use of fiber optics has been commonly known in the telecommunication industry for decades. More recently, fiber optics has been integrated into cable television networks, and it is also now used in many local area networks linking computer systems in universities, office complexes, commercial or industrial plants, etc.
Communication using fiber optics entails sending a signal in the form of light from one end of a transparent fiber (made of glass or plastic, for example) to the other end of the fiber. A light source can include a light emitting diode (LED) or a laser, for example, that provides a signal converted into light pulses. A fiber optic cable that houses the fiber guides the light pulses from the light source to a receiver at the other end. Repeaters can be used in the cable to prevent loss of strength. The receiver can then convert the light pulses back into the original signal.
There are two main types of fiber used for fiber optics: single mode fiber (SMF) and multimode fiber (MMF). A single mode fiber is very narrow in diameter (approximately 8-10 μm), and its small core allows only one mode to propagate (i.e., one path of light). This prevents distortion and provides little signal attenuation. It also provides a higher transmission rate, covers more distance, and carries higher bandwidth than multimode fiber. However, using single mode fiber costs more and can require a light source with a narrow spectral width.
Multimode fiber has a larger diameter than a single mode fiber (approximately 5-100 μm), and can provide high bandwidth at high speed over short distances. Multimode fiber is rated by its bandwidth per unit length, with categories ranging from OM1 (62.5 (core diameter)/125 μm (cladding diameter)) to OM2 (50/125 μm) to OM3 (laser optimized 50/125 μm) to OM3+ (extended reach), based on standard ISO 11801. In a multimode fiber, light waves travel in numerous paths, or modes, through the fiber. It is typically used for short range, low data rate applications because the spread in delays of signals propagating on the various modes causes dispersion or pulse broadening, leading to limited bandwidth. Over long distances, signal distortion due to the multiple modes can result in data transmission errors. However, use of multimode fiber generally costs less than use of single mode fiber.
Therefore, systems and methods are needed that take advantage of the low cost of using MMF in communication systems while avoiding the issues with MMF described above.